Beauty and misery of adipose tissue

Abstract

Introduction. Adipose tissue is an active endocrine organ. There are four types of adipose cells –white (WAT), brown (BAT), beige and pink (PAT). WAT can be subcutaneous or visceral and is seen in abundance and stored as triglycerides (TG). BAT is seen mainly in infants and helps in thermoregulation by non-shivering thermogenesis. The third kind of adipocyte, known as beige adipocyte, can appear in WAT in response to thermogenic stimulations. PAT is described as a cell with high energy storage potential. Objective of study. To analyze the advantages of BAT, PAT, and beige AT, and the disadvantages of WAT and its role in obesity. Methods and materials. Systematic literature review of the articles published in the last 10 years was conducted using the platforms PubMed and Google Scholar, focusing on advantages and disadvantages of adipose tissue. Results. The biggest advantage of BAT is the presence of uncoupling protein 1 (UCP1) which plays a major role in non-shivering thermogenesis. UCP1 activates upon stimulation and heat energy is produced in adipocytes. Beige adipose tissue results from conversion of WAT to BAT under cold exposure and beta-adrenergic receptor stimulation. During pregnancy and lactation WAT converts to PAT. PAT has also the ability to transform to WAT and BAT after lactation period. WAT stores TG as reserve. Excess accumulation causes hypertrophy and hyperplasia of the adipocytes that ultimately lead to systemic inflammation due to imbalance between pro- and anti-inflammatory cytokines. Conclusion. Adipose tissue has anatomical, functional and genetic diversity. It is a polychromatic organ that has importance in maintaining human health.